This photograph manipulation program allows not only retouching uploaded photos but also customized photographs. This is great for cover art if you want to take the time to learn how to use it.
This website provides royalty free photographs for all your needs. It gives you a huge selection and offers several pricing package options.
This graphic design website provides many template options including book covers, infographics, posters, post cards, and Facebook headers just to name a few. It is free to use and you only pay when you download your design. A photograph gallery to draw from and user friendly.
My Ecover Maker
This website provides templates for both 2-D flat book covers and 3-D book covers as well as displays for sales promotions. I have used the demo and found it very easy to use.
PSD – Book Cover Creator
Creates book cover graphics in 3D.